# Credits & Acknowledgements PocketTracker stands on a lot of excellent open-source work. Thank you to everyone below. --- ## Libraries | Library | License | Use in PocketTracker | |---|---|---| | [Oboe](https://github.com/google/oboe) | Apache 2.0 | Low-latency Android audio stream | | [DaisySP](https://github.com/electro-smith/DaisySP) | MIT **and** LGPL-2.1 (mixed — see note) | SVF filter, ReverbSc, DelayLine, Compressor, Limiter, BitCrush | | [TinySoundFont](https://github.com/schellingb/TinySoundFont) | MIT | SF2 / SoundFont2 synthesizer (with per-channel rendering fork) | | [KissFFT](https://github.com/mborgerding/kissfft) | BSD-3-Clause | FFT for spectrum analyzer and transient detection | | [Soundpipe](https://github.com/PaulBatchelor/Soundpipe) (pareq stub) | MIT | Parametric EQ biquad | | [Dragonfly Reverb](https://github.com/michaelwillis/dragonfly-reverb) | GPL-3.0 | The HALL, ROOM, PLATE and FOIL reverbs | | [Freeverb3](https://www.nongnu.org/freeverb3/) | GPL-2.0-or-later | The reverb building blocks under Dragonfly Reverb | | [skoomaDust](https://github.com/skoomabwoy/skoomaDust) | GPL-3.0 | Lo-fi effect chain; includes APComp FET compressor by Alain Paul (BSD-3-Clause) | | [dr_libs](https://github.com/mackron/dr_libs) (dr_mp3 / dr_flac) | Public domain (MIT-0) | Native MP3 / FLAC decoding | | [stb_vorbis](https://github.com/nothings/stb) | Public domain (MIT) | Native OGG Vorbis decoding | | [libogg / libopus / opusfile](https://opus-codec.org/) | BSD-3-Clause | Native Opus decoding | | [FAAD2](https://github.com/knik0/faad2) | GPL-2.0-or-later | AAC decoding — the audio track of `.m4a` and `.mp4` | | [minimp4](https://github.com/lieff/minimp4) | CC0-1.0 (public domain) | ISO-BMFF container demuxing that feeds FAAD2 | | [stb_image](https://github.com/nothings/stb) | Public domain (MIT) | Decoding theme, touch-skin and CRT-overlay PNGs | | [stb_truetype](https://github.com/nothings/stb) | Public domain (MIT) | Rasterizing the touch skin's button-label glyphs | | [Liberation Sans](https://github.com/liberationfonts/liberation-fonts) | SIL OFL 1.1 | The letters and arrows on the touch control layout | | [QuinqueFive](https://ggbot.itch.io/quinquefive-font) by GGBotNet | SIL OFL 1.1 | The 5×5 pixel font the interface is drawn in, adapted from it | | [nlohmann/json](https://github.com/nlohmann/json) | MIT | Parsing `.ptp` / `.pti` project + instrument JSON | | [SDL2](https://www.libsdl.org/) | zlib | Window, renderer, audio device, controller and keyboard input on every platform | | [AndroidX Core-KTX](https://developer.android.com/jetpack/androidx/releases/core) | Apache 2.0 | Window-insets handling in the Android launcher activity | | [AndroidX Core-SplashScreen](https://developer.android.com/jetpack/androidx/releases/core) | Apache 2.0 | Android 12+ splash-screen compatibility | Each library keeps its own license. PocketTracker as a whole is distributed under GPL-3.0-or-later (see [`LICENSE`](LICENSE)). **Full notices for everything compiled into PocketTracker — the audio engine and the SDL shell alike, across all four packages — are in [`docs/licenses/THIRD-PARTY-NOTICES.md`](docs/licenses/THIRD-PARTY-NOTICES.md),** which is the single source of truth and travels inside every release artifact. **Oboe and the two AndroidX rows are Gradle-resolved rather than compiled from `native/`**, so they exist only in the APK. Apache-2.0 §4(a) requires that a copy of the License reach anyone who receives the binary, and naming it here does not do that — **the full Apache-2.0 text is in the notices file**, which is why the notices cover them too despite not being engine code. This file ships beside the notices in every artifact rather than only in the repo — `assets/licenses/CREDITS.md` in the APK, and `licenses/CREDITS.md` in the Windows zip, the Linux tarball and the PortMaster zip. > **Note on DaisySP:** it is not uniformly MIT. Of the eight files PocketTracker compiles, five are > MIT (`svf`, `overdrive`, `decimator`, `limiter`, `crossfade`) and **three are LGPL-2.1** — > `compressor` (GRAME / Centre National de Creation Musicale), `balance` (Barry Vercoe, john ffitch, > Gabriel Maldonado) and `reverbsc` (Sean Costello, Istvan Varga, Paul Batchelor) — because those > descend from Csound and Faust rather than from Electrosmith's own code. LGPL-2.1 §3 permits > applying the ordinary GPL v2 "or any later version", so they are distributed here under > GPL-3.0-or-later along with the rest of the app. Per-file detail in the notices file above. --- ## DSP algorithm references - **SOLA time-stretch** — Roucos & Wilgus (1985), Verhelst & Roelands (1993). The "Akai-cyclic" mode matches the algorithm used in Akai S950 / S1000 samplers; the characteristic grit on jungle breaks is intentional. - **Biquad filter design** — Robert Bristow-Johnson, *Audio EQ Cookbook* (1994, rev. 2016). - **OTT 3-band compressor** — parameters matched to the Xfer Records vitOTT plugin. Downward: −27 dBFS / 8:1; upward: −35 dBFS / 4:1; ~8 dB neutral zone. - **Spectral flux transient detection** — Brossier et al., "Fast labelling of notes in music signals," ICASSP 2004. --- ## Contributors - [@skoomabwoy](https://github.com/skoomabwoy) — authored the [skoomaDust](https://github.com/skoomabwoy/skoomaDust) lo-fi effect chain integrated into PocketTracker; ongoing technical advice throughout the project. --- ## Inspiration - [Dirtywave M8](https://dirtywave.com/) — the portable tracker that proved the concept. - [LGPT / Little Piggy Tracker](https://github.com/Mdashdotdashn/LittleGPTracker) — open-source tracker heritage. - [LSDJ](https://www.littlesounddj.com/) — the Game Boy tracker that defined the form. ### Public audio source metadata [TeamNewPipe/NewPipeExtractor](https://github.com/TeamNewPipe/NewPipeExtractor), v0.27.0, GPL-3.0-or-later, provides public YouTube search/playlist/audio metadata. Source/dependency provenance and full notices are in `vendor/newpipe-extractor` and `docs/licenses/NewPipe-*.txt`. The integration supplies no login or DRM handling. ## Pocket Tracker Extreme Pocket Tracker Extreme is an independent GPL-3.0-or-later fork of [PocketTracker](https://github.com/conanizer/pockettracker), by conanizer and its contributors. Original authorship and the notices above remain intact. Extreme direction, musical concept, curation and public artist credit: **Kid Bunka**. Development and documentation include AI-assisted implementation and review. The Extreme extensions include studio synthesis, live editing, performance processing, detailed sample workflows, groove generation, mastering and source browsing. DSP adapted from Mutable Instruments is credited separately in `docs/licenses/Mutable-Instruments-PROVENANCE.txt`; module names describe source heritage and do not imply endorsement. The optional Mint Afterhours demo project has its own CC-BY-4.0 content notice inside that separate download. A user's sample library is not part of this software release. SOLIS, KNULLI and PortMaster are independent projects and are not included in the Extreme application source or binary packages.